Method Basics

In Oracle8, methods can also be used in comparative operations when used with user-defined object types. In the traditional relational model, scalar values of type VARCHAR2 and NUMBER were easy to compare and contrast. This simplicity diminishes when the data types are more complex. Map and Order methods comprise the set of comparison type methods. Map methods provide a way to compare two objects to determine a quantitative outcome. For example, let's say you defined an object type of VEHICLE, you might specify an attribute that describes the maximum speed. Map methods could perform a comparison to determine the vehicle with the fastest or slowest maximum speed. Order methods offer a different perspective. Order methods use internal logic to compare two objects. Order methods are well-suited for making comparisons of small groups of instances against a single value. An order method returned value is not quantitative but, rather, qualitative. In other words, a return value would simply state that object A is less than object B (return value of -1), objects A and B are the same/equal (return value of 0), or object A is greater than object B (return value of 1).

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